Photosensitive device

This application claims the benefit of U.S. Provisional Application No. 63/386,921, filed 12, December 2022, and the entirety of which is incorporated by reference herein.

The present disclosure relates to a photosensitive device to measure users' physiological data, and use coating technology to achieve a reduction in the light-receiving angle and enhance physiological signals.

The demand for using wearable electronic products to measure users' physiological data is gradually increasing. Specifically, these wearable electronic products obtain signals related to physiological data by measuring light reflected from the user's body (e.g., wrist). However, due to the complexity of human tissue, not all light reflected by the user's body may form useful signals.

An embodiment of the present disclosure provides a photosensitive device. The photosensitive device includes a sensing stack, an anti-reflective layer, an optical filter, a first electrode, and a second electrode. The sensing stack includes a first semiconductor layer, an intrinsic semiconductor layer disposed on the first semiconductor layer, and a second semiconductor layer disposed on the intrinsic semiconductor layer. The anti-reflective layer is disposed on a side of the sensing stack. The optical filter is disposed on the anti-reflective layer and blocks input light with an incident angle of greater than 50 degrees. The first electrode and the second electrode are disposed on the sensing stack.

The photosensitive device of the present disclosure can be applied to various types of electronic devices. In order to make the features and advantages of the present disclosure more comprehensible, various embodiments are specially cited below, together with the accompanying drawings, to be described in detail as follows.

The following disclosure provides many different embodiments or examples for implementing the provided photosensitive device (PD). Specific examples of features and their configurations are described below to simplify the embodiments of the disclosure, but certainly not to limit the disclosure.

The terms “about”, “substantially”, or the like used herein generally means within 10%, within 5%, within 3%, within 2%, within 1%, or within 0.5% of a given value or a given range. The value given herein is an approximate value, that is, the meanings of “about” or “substantially” may still be implied without the specific descriptions of “about” or “substantially”.

1 FIG. 1 1 is a schematic diagram showing the wearable electronic product with the light-emitting device (LED) and the photosensitive device (PD) according to some embodiments of the existing technology. As shown in the figure, the wearable electronic product emits a light L with specific wavelength through a light-emitting device thereof. Then, the light L penetrates the user's skin and interacts (e.g., reflects) with the user's body (especially the blood at deep skin). Subsequently, the wearable electronic product receives the reflected light RLthrough a photosensitive device (also called a photodetector) thereof. As a result, the wearable electronic product can determine the user's physiological characteristics based on a signal corresponding to the reflected light RL, such as heart rate, blood oxygen, blood sugar, water content, and blood pressure.

2 3 4 However, the reflected lights received by the photosensitive device may not all be reflected from the user's blood at deep skin, which may further include the reflected light RLof the surrounding environment (e.g., from the sun), internally reflected light RLof the wearable electronic product itself (e.g., from a glass plate G of the wearable electronic product), reflected light RLof the user's tissue at superficial skin, and other possible reflected light. In other words, the signals used to represent the user's physiological characteristics that are generated from the reflected lights include effective signals that can be used to represent the user's physiological characteristics and ineffective signals that cannot be used to represent the user's physiological characteristics.

1 2 3 4 Among these signals, only the signal generated by the reflected light RLfrom the user's blood at deep skin is effective, and this signal is an alternating signal (AC) corresponding to the cardiac systolic and diastolic. The other signals generated by the reflected light RLfrom the surrounding environment, the reflected light RLfrom the wearable electronic product itself, and the reflected light RLfrom the user's skin tissue at superficial skin, etc. are ineffective, and these signals are direct signals (DC).

2 FIG. 2 FIG. 2 FIG. is a schematic diagram showing the photoplethysmography (PPG) signal according to some embodiments of the existing technology. As shown in, the heart rate (HR) may be presented by the distance between two adjacent hills of the PPG signal, and the heart rate is related to the AC value. Therefore, the perfusion index (PI) is defined as AC divided by DC, wherein the value of PI is positively related to the quality of the photoplethysmography signal that is used to present the user's physiological characteristics. In other words, when the proportion of the AC signal is higher (that is, the higher the PI value), the accuracy of the heart rate is higher. In some cases, the quality of the photoplethysmography signal may also be represented by signal-noise ratio (SNR). In the embodiment of, the AC signal only accounts for a small part (e.g., 40%) of the total measured range of the total range of the photosensitive device, while the DC signal accounts for more than half of the total measured range. That means the quality of the photoplethysmography signal is too low, and the effect of signal processing in the back end is limited.

1 In order to solve at least the above-mentioned problems, the present disclosure provides a photosensitive device with a collimation structure (i.e., optical film), which can effectively block light having an incident angle that is greater than a specific angle (e.g., 50 degrees), thereby effectively selecting the reflected light (e.g., the reflected light RL) that can represent the user's physiological characteristics.

3 3 FIGS.A andB 3 FIG.A 3 FIG.B are schematic diagrams showing the principle of the collimation structure (i.e., optical film). As shown in, through the arrangement of the high refractive films H and the low refractive films L that are alternately stacked, the incident light IL may interact with the interfaces of any two adjacent films to form the reflect lights RL′ to RL″″. As shown in, each reflect light (i.e., the reflect lights RL′ to RL″″) has a specific incident angle θ for the photosensitive device. Therefore, the function of selecting the reflected light may be achieved by adjusting the arrangement of the high-refractive film and the low-refractive film to shield some reflected light having the specific incident angle θ. The specific instructions will be explained in detail hereinafter.

4 FIG. 4 FIG. 1 11 12 13 14 15 1 10 10 10 10 a a is a schematic diagram showing the photosensitive device according to some embodiments of the present disclosure. As shown in, the photosensitive deviceincludes the sensing stack, the anti-reflective layer, the optical filter, the first electrode, and the second electrode. In some embodiments, the photosensitive devicefurther includes the substratethat is used to carry the components or features located thereon. In some embodiments, the substratemay be a printed circuit board (PCB), thin film transistor glass (TFT glass), complementary metal oxide semiconductor (CMOS) substrate, or other suitable substrates, but the present disclosure is not limited thereto. In some embodiments, the material of the substratemay be or may include glass, polymer, other suitable substrates, or combinations thereof, but the present disclosure is not limited thereto. For example, the substratemay be a glass substrate.

4 FIG. 11 10 11 11 As shown in, the sensing stackis disposed on the substrate. More specifically, the sensing stackis configured to receive the reflected light (hereinafter, it is also called “input light”) to generate a corresponding signal that refers to the user's physiological characteristics. In some embodiments, the sensing stackis also called a photosensitive element that exhibits physical changes according to receiving light (e.g., produces an electric current). In some embodiments, the input light is in one of the following ranges: 495 nm to 570 nm, 600 nm to 750 nm, 760 nm to 1000 nm, 1050 nm to 1200 nm, 1250 nm to 1450 nm, and 1500 nm to 1700 nm, but the present disclosure is not limited thereto. In other words, the input light used to present the user's physiological characteristics may be green light, red light, infrared red (IR) light, or a combination thereof.

4 FIG. 11 110 111 110 112 111 110 112 110 112 As shown in, the sensing stackincludes the first semiconductor layer, an intrinsic semiconductor layerdisposed on the first semiconductor layer, and the second semiconductor layerdisposed on the intrinsic semiconductor layer. In some embodiments, the first semiconductor layerand the second semiconductor layermay be an n-type semiconductor layer and a p-type semiconductor layer, respectively. Alternatively, the first semiconductor layerand the second semiconductor layermay be a p-type semiconductor layer and an n-type semiconductor layer, respectively.

In some embodiments, the n-type semiconductor layer may include: group II-VI materials, such as zinc selenide (ZnSe); or group III-V materials, such as gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), or aluminum indium gallium nitride (AlInGaN), but the present disclosure is not limited thereto. In some embodiments, the n-type semiconductor layer may contain dopants such as silicon (Si) or germanium (Ge), but the present disclosure is not limited thereto. In addition, the n-type semiconductor layer may have a single-layer or multi-layer structure.

In some embodiments, the p-type semiconductor layer may include group II-VI materials, such as zinc selenide (ZnSe); or group III-V materials, such as gallium nitride (GaN), aluminum nitride (AlN), indium nitride (InN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), or aluminum indium gallium nitride (AlInGaN), but the present disclosure is not limited thereto. In some embodiments, the p-type semiconductor layer may contain magnesium (Mg), carbon (C) and other dopants, but the present disclosure is not limited thereto. In addition, the p-type semiconductor layer may have a single-layer or multi-layer structure.

111 111 111 1-x In some embodiments, the intrinsic semiconductor layermay include at least one undoped semiconductor layer or at least one low-doped layer. For example, the intrinsic semiconductor layermay be a quantum well (QW) layer, which may include indium gallium nitride (InxGaN), gallium nitride (GaN), aluminum gallium nitride (AlGaN), or aluminum indium gallium nitride (AlInGaN), but the present disclosure is not limited thereto. Alternatively, the intrinsic semiconductor layermay also be a multiple quantum well (MQW) layer.

4 FIG. 12 11 11 11 12 12 11 As shown in, the anti-reflection layeris disposed on a side of the sensing stackand configured to reduce reflection of the input light from the surface of the sensing stack, so as to increase the light receiving the amount of the sensing stack. In some embodiments, the anti-reflection layermay include semiconductor materials, organic insulating materials, or inorganic insulating materials, but the present disclosure is not limited thereto. In some embodiments, the semiconductor material may include amorphous silicon, but the disclosure is not limited thereto. In some embodiments, the organic insulating material may include acrylic polymer, polyimide, polyester, epoxy resin, combinations thereof, or other suitable organic insulating materials. In some embodiments, inorganic insulating materials suitable for the anti-reflective layermay include silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, combinations thereof, or other suitable inorganic insulating materials. For example, the material of the anti-reflective layerincludes silicon nitride.

1 12 1 12 1 12 In some embodiments, the thickness tof the anti-reflective layeris from 50 nm to 100 nm. For example, the thickness tof the anti-reflective layermay be 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, or any value or range between any two of the above-mentioned values, but the present disclosure is not limited thereto. In some embodiments, the thickness tof the anti-reflective layermay correspond to ¼λ, ¾λ, 5/4λ, 7/4λ, etc. of the wavelength of the input light to be received.

4 FIG. 13 12 13 As shown in, the optical filteris disposed on the anti-reflective layerand configured to block input light with an incident angle of greater than 50 degrees. In the present disclosure, the phrase “block input light with an incident angle of greater than 50 degrees” refers to making the transmittance of the optical filter for input light with an incident angle of greater than 50 degrees lower than 50%. For example, the transmittance of the optical filterfor input light with an incident angle of greater than 50 degrees may be 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 1%, 0.1%, or any value or range between any two of the above-mentioned values, but the present disclosure is not limited thereto.

5 FIG. 5 FIG. 6 FIG. 6 FIG. 13 13 13 13 13 13 13 1 13 13 13 is a schematic diagram showing an optical filter according to some embodiments of the present disclosure. As shown in, in some embodiments, the optical filterincludes high refractive filmsH and low refractive filmsL alternately stacked, and the total number of the high refractive filmsH and the low refractive filmsL is thirteen or more than thirteen. For example, the total number of the high refractive filmsH and the low refractive filmsL may be 13 as shown in(i.e., the spectrumstoin the figure), whereinis a cross-section view of the optical filter obtained by the scanning electron microscope (SEM) according to some embodiments of the present disclosure. However, the present disclosure is not limited thereto. In other embodiments, the total number of the high refractive filmsH and the low refractive filmsL may be 14, 15, or more than 15, but the present disclosure is not limited thereto.

13 13 13 13 13 13 In some embodiments, the refractive index of the high refractive filmsH and low refractive filmsL is from 1.3 to 2.5, but the present disclosure is not limited thereto. More specifically, the refractive index of the high refractive filmsH is from 2.0 to 2.5 and the refractive index of the low refractive filmsL is from 1.3 to 1.5. For example, the refractive index of the high refractive filmsH may be 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, or any value or range of any two of the above-mentioned values. For example, the refractive index of the low refractive filmsL may be 1.3, 1.35, 1.4, 1.45, 1.5, or any value or range of any two of the above-mentioned values.

5 FIG. 2 13 2 13 13 13 13 13 As shown in, in some embodiments, the thickness tof the optical filteris from 1500 nm to 1950 nm, but the present disclosure is not limited thereto. For example, the thickness tof the optical filtermay be 1500 nm, 1550 nm, 1600 nm, 1650 nm, 1700 nm, 1750 nm, 1800 nm, 1850 nm, 1900 nm, 1950 nm, or any value or range of any two of the above-mentioned values. In some embodiments, the thicknesses of any two of the high refractive filmsH are different. In some embodiments, the thicknesses of any two the low refractive filmsL are different. In some embodiments, the thicknesses of the high refractive filmsH are different from the thicknesses of the low refractive filmsL.

13 13 13 13 In some embodiments, the optical filterincludes a metal element, wherein the metal element may be or may include sodium, niobium, titanium, silver, barium, or a combination thereof. In some embodiments, the content of the metal element is from 15 wt % to 40 wt % based on the total weight of the optical filter, but the present disclosure is not limited thereto. For example, the content of the metal element may be 15 wt %, 20 wt %, 25 wt %, 30 wt %, 35 wt %, 40 wt %, or any value or range of any two of the above-mentioned values, based on the total weight of the optical filter. In some embodiments, the optical filtermay further include carbon, oxygen, silicon, or combinations thereof.

13 13 13 13 13 13 13 13 The first type of optical filterof the present disclosure is shown as an example. It should be noted that the following recipes are only used to make the present disclosure clearer and easier to understand and are not intended to limit this disclosure. In the first type of optical filter, based on the total weight of the optical filter, the content of sodium is from 0 wt % to 1.13 wt %, the content of niobium is from 0 wt % to 29.51 wt %, the content of carbon is from 21.52 wt % to 39.68 wt %, the content of oxygen is from 3.79 wt % to 38.48 wt %, and the content of silicon is from 6.33 wt % to 63.85 wt %. Based on the above-mentioned composition, various recipes of the first type of optical filterare shown in Table 1. Among them, any recipe shown in Table 1 may be used as a layer in the high refractive filmsH or the low refractive filmsL of the optical filter. For example, in the case of the optical filterwith thirteen layers, any of the recipes may be used as one of the thirteen layers.

TABLE 1 Recipe 1 Recipe 2 Recipe 3 Recipe 4 Recipe 5 Recipe 6 Recipe 7 C 39.68 29.63 21.52 22.45 26.42 31.1 32.36 O 31.38 38.48 34.9 31.38 26.02 22.64 3.79 Na 1.13 1.11 0.67 0.45 0 0 0 Si 6.33 16.31 20.2 16.21 28.84 28.18 63.85 Nb 21.47 14.47 22.7 29.51 18.72 18.08 0 Total 100% 100% 100% 100% 100% 100% 100%

13 13 13 13 Alternatively, the second type of optical filterof the present disclosure is shown as an example. In the second type of optical filter, based on the total weight of the optical filter, the content of titanium is from 16.40 wt % to 36.36 wt %, the content of silver is from 0 wt % to 2.38 wt %, the content of carbon is from 1.54 wt % to 27.47 wt %, the content of oxygen is between 31.46 wt % and 47.01 wt %, and the content of silicon is from 12.92 wt % to 42.99 wt %, and the average and the standard deviation of the compositions of the second type of optical filterare shown in Table 2.

TABLE 2 Standard Max Min Average Deviation C 27.47 1.54 6.69 7.37 O 47.01 31.46 42.77 4.63 Si 42.99 12.92 24.75 9.72 Ti 36.36 16.4 24.93 5.09 Ag 2.38 1.42 1.9 —

13 13 13 13 Alternatively, the third type of optical filterof the present disclosure is shown as an example. In the third type of optical filter, based on the total weight of the optical filter, the content of titanium is from 18.93 wt % to 20.93 wt %, the content of silver is from 0.26 wt % to 2.26 wt %, the content of barium is from 1.10 wt % to 3.10 wt %, the content of carbon is from 23.28 wt % to 25.28 wt %, the content of oxygen is from 34.09 wt % to 36.09 wt %, and the content of silicon is from 16.33 wt % to 18.33 wt %, and the average of the compositions of the third type of optical filterare shown in Table 3.

TABLE 3 Max Min Average C 18.33 16.33 17.33 O 36.09 34.09 35.09 Si 25.28 23.28 24.28 Ti 20.93 18.93 19.93 Ag 0.26 2.26 1.26 Ba 3.1 1.1 2.1

13 13 It should be noted that, although the three types of the optical filterare provided here before, all of them are only given to make the disclosure clearer and easier to understand and are not intended to limit the disclosure. In other words, any optical filter that may block input light with an incident angle of greater than 50 degrees may be used as the optical filterof the present disclosure. Hereafter, the principle of blocking input light with an incident angle of greater than 50 degrees by the optical filter is described.

7 FIG. 7 FIG. 7 FIG. 7 FIG. 13 13 11 11 is a schematic diagram showing the relationship between the spectrum shift and the transmittance. As shown in, when the input light penetrates (passes through) the optical filterdescribed above by different incident angles, the entire spectral curve of the input light shifts toward the left (i.e., toward short wavelength), which shows the blueshift phenomenon. On the other hand, different wavelengths of the input light correspond to different transmittances. As a result, when the same input light penetrates the optical filterby different incident angles, the amounts of the input light (i.e., the strength of the input light) at a specific wavelength that can be received by the sensing stackare different, which means that the receiving of the input light having an unexpected incident angle by the sensing stackcan be reduced. For example, the input light with the incident angle at 0 degrees is shown as the solid line in, the input light with the incident angle at 30 degrees and the input light with the incident angle at 60 degrees are shown as the dotted lines in. The peak of the solid line with the wavelength at 660 nm is shifted to the peaks of the dotted line with the wavelength at 630 nm or 570 nm based on the blueshift phenomenon. Accordingly, at the wavelength of 660 nm, the transmittance of the input light with the incident angle at 0 degrees (about 100%) is greater than the transmittance of the input light with the incident angle at 30 degrees (about 50%) and the transmittance of the input light with the incident angle at 60 degrees (about 10%).

8 FIG. 9 FIG. 8 FIG. 8 FIG. 9 FIG. 8 FIG. 9 FIG. 13 13 Taking theandas another example. Among them, diagram (A) ofis a schematic diagram showing the spectrum of the input light at 460 nm to 620 nm before penetrating the optical filter, diagram (B) ofis schematic diagrams showing the transmittances of the input light at 460 nm to 620 nm with different incident angles after penetrating the optical filter, diagram (C) ofis the same as the diagram (B) of, and diagram (D) ofis a schematic diagram showing the transmittances of the input light at 540 nm with different incident angles after penetrating the optical filter. As shown in diagram (A) and diagram (B), when the input light shown in diagram (A) penetrates the optical filter, the spectrum of the input light at 520 nm, 540 nm, and 560 nm are shown in diagram (B). Meanwhile, the blueshift of the spectrum of the same input light at 520 nm, 540 nm, and 560 nm that penetrates the optical filterwith different incident angles is considered (as shown in diagram (B)). Then, taking the sensing stack using a light with 540 nm for determining the user's physiological characteristics as an example, the spectrum of the input light with different incident angles at 540 nm is shown in diagram (D), wherein the spectrum of diagram (D) is drawn by catching specific nodes (i.e., at 540 nm) of the spectrums of input lights with different incident angles of diagram (C) (i.e. diagram (B)). In diagram (D), the different transmittances of the same input light having different incident angles is shown, and the transmittances of the input light having incident angles of 0 degrees to 30 degrees are greater than the transmittances of the input light having incident angles of 30 degrees to 70 degrees. As mentioned above, the function of blocking the input light having incident angles greater than a specific angle (e.g., 50 degrees) may be achieved.

4 FIG. 14 110 15 112 13 14 15 14 15 14 15 14 15 13 11 As shown in, the first electrodeis disposed on and electrically connected to the first semiconductor layer, and the second electrodeis disposed on and electrically connected to the second semiconductor layerand exposed from the optical filter. In some embodiments, the first electrodeand the second electrodeare respectively the cathode electrode and the anode electrode. However, the present is not limited thereto. In some other embodiments, the first electrodeand the second electrodemay be respectively the anode electrode and the cathode electrode. In some embodiments, there is no coating provided on the first electrodeand the second electrode. In other words, the first electrodeand the second electrodedo not directly contact with any coating such as the above-mentioned optical filteror anti-refractive layer.

14 15 2 In some embodiments, the first electrodeor the second electrodemay be include conductive material. The conductive material may include metal, metal compounds, combinations thereof, or other suitable conductive materials, but the disclosure is not limited thereto. For example, the metal may be tin (Sn), copper (Cu), gold (Au), silver (Ag), nickel (Ni), indium (In), platinum (Pt), palladium (Pd), iridium (Ir), titanium (Ti), chromium (Cr), tungsten (W), aluminum (Al), molybdenum (Mo), titanium (Ti), magnesium (Mg), zinc (Zn), germanium (Ge), or their alloys, but the present disclosure is not limited thereto. For example, the metal compound may be tantalum nitride (TaN), titanium nitride (TiN), tungsten silicide (WSi), indium tin oxide (ITO), antimony zinc oxide (AZO), Tin oxide (SnO), zinc oxide (ZnO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), indium tin zinc oxide (ITZO), antimony tin oxide (ATO), etc., but the present disclosure is not limited thereto.

10 FIG. 4 FIG. 10 FIG. 1 16 111 112 12 16 16 112 a is a top view showing the photosensitive device according to some embodiments of the present disclosure. As shown inand, in some embodiments, the photosensitive devicefurther includes the dielectric ringdisposed on the intrinsic layerand surrounding the second semiconductor layer. In some embodiments, the anti-reflective layercovers the top surface of the dielectric ring. More specifically, the dielectric ringmay be provided to prevent the second semiconductor layerfrom unintended electrical connections with other components (not shown) to avoid device failure.

16 16 In some embodiments, the material of the dielectric ringmay be or may include nitride or oxide, but the present disclosure is not limited thereto. For example, the dielectric ringmay be or may include silicon oxide (silicon oxide), silicon nitride (silicon nitride), or silicon oxynitride (SiON).

11 FIG. 11 FIG. 1 2 3 4 is a schematic diagram showing the wearable electronic product with the light-emitting device and the photosensitive device according to some embodiments of the present disclosure. As shown in, compared with the wearable electronic product of existing technology (i.e., the photosensitive device provided without an optical filter), the wearable electronic product of the present disclosure may receive the reflected light RLfrom the user's blood at deep skin, while effectively reducing the receiving of reflected light that is unexpected such as the reflected light RLof the surrounding environment (e.g., from the sun), the internally reflected light RLof the wearable electronic product itself (e.g., from a glass plate of the wearable electronic product), the reflected light RLof the user's tissue at superficial skin, and other possible reflected light.

12 FIG. 12 FIG. 12 FIG. is a schematic diagram showing the photoplethysmography (PPG) signal according to some embodiments of the present disclosure. As shown in, by the arrangement of the present disclosure, the AC signal may account for a big part (e.g., greater than 60%) of the total measured range of the total range of the photosensitive device, while the DC signal accounts for less than half of the total measured range. As shown in, after enlarging the intensity of the signal (AC+DC) from the photosensitive device provided with an optical filter to be 100% of the intensity of the signal (AC+DC) from the photosensitive device provided without an optical filter, the AC signal will be very significant, which helps in the identification of physiological characteristics.

13 15 FIGS.- 13 15 FIGS.- are schematic diagrams showing the normalized perfusion indexes (PI) of the green-light LED, red-light LED, and IL-light LED. In the present disclosure, the normalized perfusion indexes (PI) indicates the PI ratio that equals the PI value of the photosensitive device provided with an optical filter divided by the PI value of the photosensitive device provided without an optical filter. As shown in, no matter which light source the wearable device uses (for example, green light, red light, or infrared light), PI may be significantly improved. For example, the PI ratio of the green light of the photosensitive device provided with an optical filter is at least 123.7%. Similarly, the PI ratio of the red light of the photosensitive device provided with an optical filter is at least 121.9%. Similarly, the PI ratio of the IL light of the photosensitive device provided with an optical filter is at least 116.2%. In this way, the significant improvement of PI significantly improves the identification of physiological characteristics.

16 FIG. 16 FIG. 16 FIG. 4 FIG. 16 FIG. 1 10 12 13 14 15 111 110 a is a schematic diagram showing the photosensitive device according to some other embodiments of the present disclosure. As shown in, the photosensitive device′ includes the substrate, the anti-reflective layer, the optical filter, the first electrode, and the second electrode. More specifically, the difference between the photosensitive device shown inand the photosensitive device shown inis that the intrinsic semiconductor layeris surrounded by the first semiconductor layerin.

17 FIG. 18 FIG. 17 18 FIGS.- 1 10 12 13 14 15 14 15 110 111 b is a schematic diagram showing the photosensitive device according to some other embodiments of the present disclosure, andis a bottom view showing the photosensitive device according to some embodiments of the present disclosure. As shown in, the photosensitive deviceincludes the substrate, the anti-reflective layer, the optical filter, the first electrode, and the second electrode. More specifically, in these embodiments, the first electrodeand the second electrodeare both on the same side of the first semiconductor layeropposite the intrinsic layer.

17 18 FIGS.- 1 13 b In these embodiments of, the arrangement of the photosensitive deviceis called a flip-type structure. In other words, the optical filterof the present disclosure may be not only used in the vertical-type structure of the photosensitive device but also in the flip-type structure of the photosensitive device.

19 FIG. As mentioned above, the measured signal feedback may be improved by the photosensitive device provided with an optical film, so the distance between the light-emitting element and the light-receiving element (i.e., the sensing stack) may be shortened to reduce the overall module design.is schematic diagrams showing the photosensitive device according to some embodiments of the present disclosure.

19 FIG. 19 FIG. As shown in, due to the DC signal decrease significantly and the AC signal decrease slightly, the noise decreases significantly. Therefore, the distance between the light-emitting element (LED) and the light-receiving element (PD) may be shortened as but not limited to the way shown in (A) and (B) of.

20 FIG. 20 FIG. is a schematic diagram showing the wafer coated with an optical film according to some embodiments of the present disclosure. As shown inand Table 4, the measurement of the light-receiving angle of the sensing element, the light-receiving angle is significantly converged when the collimation structure is provided. For example, in area A of the wafer and area B of the wafer, the light-receiving angle of the photosensitive device with a collimation structure (i.e., optical film) is significantly lower than the light-receiving angle of the photosensitive device without a collimation structure (i.e., optical film).

TABLE 4 measurement of light-receiving angle (half angle) Wafer Position Item Angel No. Green-light Red-light IR-light without collimation without No. 1 58.5 61.5 58.5 structure (i.e., optical glue No. 2 57 58.5 60 film) with glue No. 1 60 61.5 61.5 No. 2 60 60 61.5 with upper area without No. 1 40.5 25.5 33 collimation A of wafer glue No. 2 40.5 25.5 34.5 structure with glue No. 1 42 27 37.5 (i.e., No. 2 40.5 25.5 38 optical lower area without No. 1 37.5 22.5 33 film) B of wafer glue No. 2 37.5 25.5 31.5 with glue No. 1 37.5 24 31.5 No. 2 39 24 36

In summary, the present disclosure provides a photosensitive device that can block input light having an incident angle greater than 50 degrees, so as to effectively measure the user's physiological characteristics. In addition, due to the measured signal feedback being enough, the distance between the light-emitting element and the light-receiving element (i.e., the sensing stack) may be shortened to reduce the overall module design. Moreover, the angle of light blocked by the optical filter may be changed to target reflected light from different skin depths.

While the disclosure has been described by way of example and in terms of the preferred embodiments, it should be understood that the disclosure is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.